Cyanide adsorption from aqueous solution using mesoporous zeolite modified by cetyltrimethylammonium bromide surfactant

Abstract

The purpose of this study was the modification of zeolite with the cationic surfactant of cetyltrimethylammonium bromide for enhancing the adsorption of cyanide (CN−) from aqueous solution. Hence, the batch tests were conducted under different conditions for CN− removal by the surfactant-modified zeolite (SMZ). The effect of pH (3–10), SMZ dosage (0.25–5 g/L), CN− concentration (50, 100, and 200 mg/L), and contact time (5–400 min) was evaluated. More than 95% of cyanide was removed at the conditions of pH of 10, the initial cyanide concentration of 100 mg/L, the SMZ dosage of 4 g/L, and the contact time of 250 min. The analysis of kinetics adsorption showed that cyanide ions adsorption onto the SMZ clearly followed the pseudo-second-order model. The isotherm adsorption data were mostly matched by Langmuir model with maximum adsorption capacity of 49.57 mg/g. The fresh and used SMZ was fully characterized by Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, loss of ignition, X-ray powder diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, and pH of zero point charge (pHzpc). The surface study indicated that the adsorbent is mesoporous and crystalline. The adsorption–desorption study was done using three reagents of HNO3, HCl, and NaOH. A metal plating wastewater was successfully treated using SMZ. Accordingly, the SMZ was found to be an effective adsorbent for the removal of different concentrations of cyanide from aqueous solution.